Respect? What respect?

A couple of days ago, driving along a highway, a car passed me with a large skeletal finger ‘statement’ firmly stuck on the back window.
Who was this abuse aimed at? Not me, surely? Was it just for any other car driver who happened to be in the vicinity of the ‘rude finger’ car?
What was its purpose?
What made the driver of this particular car think that this sort of visual affront was appropriate? Was he an angry man or did he think it was funny?
More questions popped into my mind:
Who would buy such a thing? And then stick it on the back window of a car.
And is there a particular symbolism in the finger being skeletal?
What sort of a shop would sell this? Who would design it and who originally thought it a good idea to manufacture such an offensive item?
It obviously worked as at least one person purchased it!
 
But, perhaps most of all:
What has happened to society, to civility, and courtesy?
Where is the respect towards others?
Is a sign such as this meant to annoy? Is it an insult – or there to shock and offend? Or are we just supposed to laugh?
 
I saw it as a type of abuse; disrespectful towards all who are forced to see it. It serves no other purpose other than to be offensive. So, who is behind such a stupid affront to fellow road users?
Can it possibly be simply a message to tell the world that this driver is a dull witted fool?
 
Or am I being too precious and need to ‘lighten up’?